Improvement in valve-gears for steam-engines



J. W. HACKWDRTH.

Valve-Gear for Steam-Engines.

"0135,0136. Patentedjanl2ly1873.

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UNITED. STATES PATENT OFFICE.

JOHN W. HAOKWORTH, OF DABLINGTON, ENGLAND.

IMPROVEMENT IN VALVE-GEARS FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 135,036, dated January 21, 1873.

10 all whom it may concern:

Be it known that I, JOHN W. HAGKWORTH, of Darlington, Durham county, England, temporarily residing in Jersey City, in the State of New Jersey, have invented certain Improvements relating to the Valve-Gear of Steam and Gas Engines, of which the following is a specification:

I have in Letters Patent numbered 133,529, dated December 3, 1872, described provisions for working a valve by meansbf a rod, one end of which is operated with an eccentric or crank motion, and the other is allowed to reciprocate rectilinearly. The valve-rod is attached at an intermediate point, and by changin gthe direction of the rectilineal motion of the end of the rod, the motion of the valve is modified so as to give great variation in the extent of its travel while the lead is practically uniform. That construction is open to the objection that under certain conditions one end of the cylinder receives steam considerably longer than the other. Another objection is, that for some engines it is difficult to obtain a sufficiently long travel for the valve without employing a very large eccentric and involvin g much friction.

In my present invention I have modified the construction by extending the eccentricrod beyond the pin or part which reciprocates in the changeable path, and the valve-rod is attached. to such overhanging end. By this means I can obtain, when the reciprocating path is adjusted to be exactly radial with the shaft, the same motion as in the other construction, thereby giving the proper amount of motion to allow for the lap and lead; and on changing the position of the reciprocating path, by inclining it in one direction or the other, can induce an increase in the travel of the valve with the proper motion for either forward or backward working, and with the advantage of giving a greater travel of the valve with a less amount of inclination of the reciprocating path.

The improved construction also makes the distribution of steam more equal in the two ends of the cylinder.

The following is a description of what I consider the best means of carrying out the invention.

The accompanying drawing forms a part of this specification.

Figure 1 is a side View, partly in section; and Fig. 2 is a plan View, partly in section.

The drawing shows the novel parts with so much of the ordinary parts as is necessary to show their relations thereto.

Similar letters of reference indicate like parts in both the figures.

A is a portion of the stationary frame 5 B, the main shaft; b, the single eccentric required; C, an eccentric strap and rod 5 and m, the pin to which the valve-rod is connected. The valve-rod is marked M, and leads to the slide-valve to communicate the variable motion thereto, as will be understood. D is a pin fixed atan intermediate point in the eccentric-rod G, and which is caused to reciprocate backward and forward in a changeable path. As the mechanism is here represented, the guide or path for this pin D is changed in position and inclined in one direction or the other by means of the hand-wheel, which operates through bevel-gear and a worm-wheel on a segment connected to an arm but the mechanism for thus changing the position of the path for the reciprocation of the pin D is susceptible of various changes which may be effected by any mechanic. It is only important that the path be capable of being changed to a considerable inclination in either direction, and may beheld firmly in either position. As the provisions for guiding the pin D and inclining the path are carried out in the drawing, E is a forked yoke capable of turning to a certain extent on trunnions c e, and finished on its sides to form guides for the jaws formed on the ends of the pin D. On the yoke E is a segment, E, which is controlled by the worm H receiving motion at will through the bevelgears represented from the hand-wheel H. The trunnions e 0 being mounted on fixed bear ings, as the wheel H is turned in one direction o r the other the yoke E is changed in its inclination, and consequently the pin D is caused to reciprocate in a different path and to have a greater or less amount of vertical movement. Whatever its amount of vertical or upand-down motion, the pin m and consequently the valve-rod M has a greater amount of motion. "This arrangement allows a moderately-large eccentric to give a large amount of travel to the valve.

All the modifications in the details suggested in my previous patent, referred to, may be adopted with this improved arrangement. Any construction ordinarily used for a parallel motion may be employed for the changeable path.

I claim as my invention- The within-described arrangement of the Valve-rod M, pin m, and reciprocating pin 1) on the eccentric-rod O, in combination with the eccentric b, changeable path E, and means for changing the position of the latter at Will as and for the purposes herein specified.

In testimony whereof I have hereunto set my hand this 28th day of December, 1872, in the presence of two subscribing witnesses.

JOHN W. HAOKWORTH.

Witnesses:

WM. 0. DEY, ALFD. WESTBROOK. 

